Michel Laberge is founder and chief scientist of ‘General Fusion’.
Fossil fuels are currently our major energy source, since they are convenient and cost effective. Michel suggest nuclear power – it is energy dense, reliably produces power, and creates no CO2. Fission is currently the most common type of nuclear power, but fusion would be safer since the radioactive waste is very short term and there is no risk of meltdown. The fuel could be extracted from the ocean, and power us for billions of years.
Fusion is difficult to pull off – the 2 nucleii need to be thrown together so fast that they overcome their electrostatic repulsion, which can only be done at 150 million degrees. This heat is the limiting factor that makes fusion difficult. Some ways that have been proposed are
- Magnetic fusion: charged plasma is suspended in a ring of magnets shaped like a donut, where it is heated to fusion temperatures.
- Laser fusion: a ball of matter is compressed by lasers from all directions. As it compresses it heats quickly.
Plenty of people will dismiss fusion as purely theoretical, but fusion is progressing to become more and more practical. The research has been growing at a rate similar to Moore’s law – increasing by a factor of 10 each decade (ie: developing 10 times faster than the decade before it). The science needed to build a fusion reactor is now close, but political will is now slowing us down.
Fusion is criticised as being expensive – research costing about 1 billion dollars a year, but again Moore’s law was also expensive. The technology needed to get an internet-enabled smartphone cost 1,000 billion dollars. Subsidies to fossil fuel and renewable energy industries cost 650,000 billion per year. To solve the problem of fusion would be cheap and important by comparison.
Michel did not have the resources of the large labs, so needed a cheaper solution. He criticises laser and magnetic fusion as very large and expensive, and find it difficult to contain or use the fusion energy. The neutrons shoot at high speeds and high temperature and can damage the machines – it is as if containing and using the high energy neutrons was added as an afterthought rather than the goal.
Michel investigated Magnetised Target Fusion (MTF). In MTF, you fill a vat with liquid metal, then spin it to form a vortex in the middle. Pistons on the outside of the vat then compress the metal, where it gets hotter and begins fusing. It has advantages over laser and magnetic
- the liquid metal absorbs the energy of fused neutrons, preventing damage to walls.
- The liquid metal heats up, which can then be run through a heat exchanger and used to create energy.
- Most of the energy comes from steam powered pistons, which is far cheaper than magnets or lasers.
Unfortunately MTF didn’t work: the plasma cools faster than the heat of compression, so it didn’t do anything. The improvement was to make the piston into an anvil and hammer. The pistons will accelerate and then smash into an anvil, to push all the energy into the liquid metal in one blow. This created some neutrons, which were enough for Michel to get $50 million and hire a larger team to develop the concept further. 14 hammers will be aligned around a small sphere, and the impacts need to be coordinated with precise electronics. If they fire 1 impact per second, it can produce about 100MW of electricity.
Fusion is coming – it has been done by large labs, and now smaller ones like Michel’s are showing it can be done.